I see no reason why you couldn't just shorten them, unless you've crimped them to the point that the case mouth is digging into the side of the bullet.
Of course, you should load some at the shorter length at a STARTING load and test up to the 5.2gr.
and you should start at the STARTING load for future loads.
Still happily answering to the call-sign Peetza.
The problem, as you so eloquently put it, is choice.
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.